-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 > On 200704172359, Robert J. Hansen wrote: >> 1. We are unlikely to ever be able to brute-force a 256-bit >> keyspace. Ever. Not until computers are made of something other >> than matter, occupy something other than space, run on something >> other than energy, according to rules other than physics. > > I was under the impression that quantum computers were about to > provide > a break in factorization. From quick grep on Wikipedia, I find that:
They've been "about to provide" a break in factorization for the last 30 years. > However, I assume you know what you talk about, when you say that we > aren't likely to factor 256-bit-numbers ever. So please restate > that -- > even in the face of quantum computers -- we won't ever factor 256 bit > numbers. We're already factoring 256-bit numbers. Fortunately, I didn't claim 256-bit composites would forever be secure. I claimed 256-bit keyspace searches would be secure. Keyspace search is a different set of problems than factorization. For a brute-force search the best we can do is Grover's quantum database algorithm, which reduces it down to an equivalent 128-bit keyspace. From there we use quantum thermodynamics--namely the Margolus-Levitin theorem--to get some reasonable bounds on how much time, energy, etc., are required to do it. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (Darwin) iQEcBAEBCgAGBQJGJiWiAAoJELcA9IL+r4EJCTcH/RUOxI6RNuuu2WaCpAeJLfHs 0u+KzJ6MALtonHQOkAbhDTw8zTC+OTHEuN/t2+dwli6E8r7F61RIMpLyPiZpfS0y rQjHMqJPMdr7Xerhn1haGdov2MzbvtloqHBEP9T65fstTEYBXoYMDSNhYVRV1Fpz g+is39fVr6D3LZ5W50VQhtTwmcpGM7ZKl4XSgqtv2UwwPM7dYjMQ+Qgz+5MnPLe3 wZlD06/bvrbY5InFRQFMaFhNtVAC6v42G6W8AOv8WD0kXJCopUGOwYelQ40qhdug DvXWxpApv7jgmStms63AlG3TjQemwF3rkreFsk9IClAZ5T3EpTafqVd3HC4oYBc= =OqFT -----END PGP SIGNATURE----- _______________________________________________ Gnupg-users mailing list Gnupg-users@gnupg.org http://lists.gnupg.org/mailman/listinfo/gnupg-users